A device for longitudinal pumping of a laser medium is disclosed in US 2010/0014547 A1. This device comprises several pump laser diodes which are mounted on side faces of a cooling device of the laser medium. The pump radiation emitted by said laser diodes is reflected by several parabolic mirrors toward one of the end faces of the solid state laser medium. A problem of end-pumped solid state lasers is the requirement to precisely align the pump lasers and the pump laser optic with respect to the optical mode of the laser resonator. This problem also arises in the device of US 2010/0014547 A1, in which each of the parabolic mirrors has to be precisely aligned in order to achieve the desired intensity distribution of the pump radiation at the entrance of the solid state laser medium.